Comment 1 for bug 992338

In addition to this, turning "Record Activity" on the privacy settings screen off should also inhibit additions to ~/.local/share/recently-used.xbel.

At this moment I work around the problem by

sudo chattr +i ~/.local/share/recently-used.xbel

which inhibits additions to the recently-used file.

You can change this back by

sudo chattr -i ~/.local/share/recently-used.xbel

so the next item will be added again.

This works but it is cumbersome. It would be nice if the privacy settings could take care of it. Of course, the chattr command has to be run by root which could be a problem for a simple on/off switch.